The present invention relates to producing a closed container, to said closed container, and to its constituent elements. More precisely, the present invention relates:                to a method of producing a closed container with a tight and mechanically strong seal by fastening two metal elements of the following type:        
a) a body with an essentially cylindrical or prismatic shape having a base with one or more axial walls and an open top axial end; and
b) a cover the shape of which may be more or less complex, having one or more walls to be positioned at the top axial end of said body facing the axial wall(s) of said body in the extension thereof;
which method is carried out under particular and difficult conditions;
                to said closed container with a tight and mechanically strong seal having a structure which comprises the two metal elements defined above (body, cover) fastened to each other; and        to the constituent elements of said container, considered independently and jointly, prior to said fastening, i.e.:        
a) said body;
b) said cover; the internal structure of one of said two elements including a docking guide; and
c) said docking guide per se, when used as an insert.
The present invention was developed in the context of packaging and storing nuclear waste, more precisely in the context of the invention described and claimed in European patent EP-A-0 774 761. However, the present invention is not limited to that context.
More generally, the present invention pertains to the field of packaging hazardous waste which is handled remotely, most probably with a view to storage. The body of a container, loaded with said hazardous waste (for example nuclear waste compressed into cake), open at is top axial end (and not solely with a single small diameter orifice) has to be blanked off with a cover. Said blanking off must be tight (because of the hazardous nature of said waste) and mechanically strong (the loaded closed container subsequently has to be handled by its cover). It must also be capable of being carried out in a hostile environment (primarily a nuclear environment) in an automated manner under remote control.
In the context of packaging nuclear waste in bulk in containers, said waste being bound with a binder of the glass or cement type, the filling orifices of said containers (small diameter orifices) are blanked off by positioning and welding a plate thereto. The diameter of said filling orifices is not large and the weld in question does not have to be very strong, although that weld must provide a seal. The blanking off technique employed in that context (less severe specifications) cannot directly be transposed to the context of the invention (where the specifications are particularly severe). A large surface area has to be blanked off and the seal in question must be mechanically strong.
In said context of the invention, it was initially envisaged that a conventional mechanical sealing method could be employed, involving the combined use of parts in the form of a flange, bolts, and gaskets. Such a method involves much handling and problems with ageing of the gaskets in question are unavoidable.